/* Calculate what line insertion or deletion to do, and do it, Copyright (C) 1985, 1986, 1990, 1993, 1994 Free Software Foundation, Inc.This file is part of GNU Emacs.GNU Emacs is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 2, or (at your option)any later version.GNU Emacs is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See theGNU General Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU Emacs; see the file COPYING. If not, write tothe Free Software Foundation, Inc., 59 Temple Place - Suite 330,Boston, MA 02111-1307, USA. */#include <config.h>#include "termchar.h"#include "lisp.h"#include "dispextern.h"#include "frame.h"externstructdisplay_line**ophys_lines;#define max(a, b) ((a) > (b) ? (a) : (b))#define min(a, b) ((a) < (b) ? (a) : (b))/* All costs measured in characters. So no cost can exceed the area of a frame, measured in characters. Let's hope this is never more than 1000000 characters. */#define INFINITY 1000000structmatrix_elt{/* Cost of outputting through this line if no insert/delete is done just above it. */intwritecost;/* Cost of outputting through this line if an insert is done just above it. */intinsertcost;/* Cost of outputting through this line if a delete is done just above it. */intdeletecost;/* Number of inserts so far in this run of inserts, for the cost in insertcost. */unsignedcharinsertcount;/* Number of deletes so far in this run of deletes, for the cost in deletecost. */unsignedchardeletecount;/* Number of writes so far since the last insert or delete for the cost in writecost. */unsignedcharwritecount;};/* Determine, in matrix[i,j], the cost of updating the first j old lines into the first i new lines using the general scrolling method. This involves using insert or delete somewhere if i != j. For each matrix elements, three kinds of costs are recorded: the smallest cost that ends with an insert, the smallest cost that ends with a delete, and the smallest cost that ends with neither one. These are kept separate because on some terminals the cost of doing an insert varies depending on whether one was just done, etc. *//* draw_cost[VPOS] is the cost of outputting new line at VPOS. old_hash[VPOS] is the hash code of the old line at VPOS. new_hash[VPOS] is the hash code of the new line at VPOS. Note that these are not true frame vpos's, but relative to the place at which the first mismatch between old and new contents appears. */staticvoidcalculate_scrolling(frame,matrix,window_size,lines_below,draw_cost,old_hash,new_hash,free_at_end)FRAME_PTRframe;/* matrix is of size window_size + 1 on each side. */structmatrix_elt*matrix;intwindow_size;int*draw_cost;int*old_hash;int*new_hash;intfree_at_end;{registerinti,j;intframe_height=FRAME_HEIGHT(frame);registerstructmatrix_elt*p,*p1;registerintcost,cost1;intlines_moved=window_size+(scroll_region_ok?0:lines_below);/* first_insert_cost[I] is the cost of doing the first insert-line at the I'th line of the lines we are considering, where I is origin 1 (as it is below). */int*first_insert_cost=&FRAME_INSERT_COST(frame)[frame_height-1-lines_moved];int*first_delete_cost=&FRAME_DELETE_COST(frame)[frame_height-1-lines_moved];int*next_insert_cost=&FRAME_INSERTN_COST(frame)[frame_height-1-lines_moved];int*next_delete_cost=&FRAME_DELETEN_COST(frame)[frame_height-1-lines_moved];/* Discourage long scrolls on fast lines. Don't scroll nearly a full frame height unless it saves at least 1/4 second. */intextra_cost=baud_rate/(10*4*FRAME_HEIGHT(frame));if(baud_rate<=0)extra_cost=1;/* initialize the top left corner of the matrix */matrix->writecost=0;matrix->insertcost=INFINITY;matrix->deletecost=INFINITY;matrix->insertcount=0;matrix->deletecount=0;/* initialize the left edge of the matrix */cost=first_insert_cost[1]-next_insert_cost[1];for(i=1;i<=window_size;i++){p=matrix+i*(window_size+1);cost+=draw_cost[i]+next_insert_cost[i]+extra_cost;p->insertcost=cost;p->writecost=INFINITY;p->deletecost=INFINITY;p->insertcount=i;p->deletecount=0;}/* initialize the top edge of the matrix */cost=first_delete_cost[1]-next_delete_cost[1];for(j=1;j<=window_size;j++){cost+=next_delete_cost[j];matrix[j].deletecost=cost;matrix[j].writecost=INFINITY;matrix[j].insertcost=INFINITY;matrix[j].deletecount=j;matrix[j].insertcount=0;}/* `i' represents the vpos among new frame contents. `j' represents the vpos among the old frame contents. */p=matrix+window_size+2;/* matrix [1, 1] */for(i=1;i<=window_size;i++,p++)for(j=1;j<=window_size;j++,p++){/* p contains the address of matrix [i, j] *//* First calculate the cost assuming we do not insert or delete above this line. That is, if we update through line i-1 based on old lines through j-1, and then just change old line j to new line i. */p1=p-window_size-2;/* matrix [i-1, j-1] */cost=p1->writecost;if(cost>p1->insertcost)cost=p1->insertcost;if(cost>p1->deletecost)cost=p1->deletecost;if(old_hash[j]!=new_hash[i])cost+=draw_cost[i];p->writecost=cost;/* Calculate the cost if we do an insert-line before outputting this line. That is, we update through line i-1 based on old lines through j, do an insert-line on line i, and then output line i from scratch, leaving old lines starting from j for reuse below. */p1=p-window_size-1;/* matrix [i-1, j] *//* No need to think about doing a delete followed immediately by an insert. It cannot be as good as not doing either of them. */if(free_at_end==i){cost=p1->writecost;cost1=p1->insertcost;}else{cost=p1->writecost+first_insert_cost[i];if((int)p1->insertcount>i)abort();cost1=p1->insertcost+next_insert_cost[i-p1->insertcount];}p->insertcost=min(cost,cost1)+draw_cost[i]+extra_cost;p->insertcount=(cost<cost1)?1:p1->insertcount+1;if((int)p->insertcount>i)abort();/* Calculate the cost if we do a delete line after outputting this line. That is, we update through line i based on old lines through j-1, and throw away old line j. */p1=p-1;/* matrix [i, j-1] *//* No need to think about doing an insert followed immediately by a delete. */if(free_at_end==i){cost=p1->writecost;cost1=p1->deletecost;}else{cost=p1->writecost+first_delete_cost[i];cost1=p1->deletecost+next_delete_cost[i];}p->deletecost=min(cost,cost1);p->deletecount=(cost<cost1)?1:p1->deletecount+1;}}/* Perform insert-lines and delete-lines operations on FRAME according to the costs in MATRIX, using the general scrolling method. Update the frame's current_glyphs info to record what was done. WINDOW_SIZE is the number of lines being considered for scrolling and UNCHANGED_AT_TOP is the vpos of the first line being considered. These two arguments can specify any contiguous range of lines. We also shuffle the charstarts vectors for the lines along with the glyphs; but the results are not quite right, since we cannot offset them for changes in amount of text in this line or that line. Luckily it doesn't matter, since update_frame and update_line will copy in the proper new charstarts vectors from the frame's desired_glyphs. */staticvoiddo_scrolling(frame,matrix,window_size,unchanged_at_top)FRAME_PTRframe;structmatrix_elt*matrix;intwindow_size;intunchanged_at_top;{registerstructmatrix_elt*p;registerinti,j;registerstructframe_glyphs*current_frame;/* temp_frame->enable[i] means line i has been moved to current_frame. */registerstructframe_glyphs*temp_frame;structqueue{intcount,pos;}*queue;intoffset=unchanged_at_top;intqi=0;intwindow=0;registerinttem;intnext;queue=(structqueue*)alloca(FRAME_HEIGHT(frame)*sizeof(structqueue));current_frame=FRAME_CURRENT_GLYPHS(frame);temp_frame=FRAME_TEMP_GLYPHS(frame);bcopy(current_frame->glyphs,temp_frame->glyphs,current_frame->height*sizeof(GLYPH*));bcopy(current_frame->charstarts,temp_frame->charstarts,current_frame->height*sizeof(GLYPH*));bcopy(current_frame->used,temp_frame->used,current_frame->height*sizeof(int));bcopy(current_frame->highlight,temp_frame->highlight,current_frame->height*sizeof(char));bzero(temp_frame->enable,temp_frame->height*sizeof(char));bcopy(current_frame->bufp,temp_frame->bufp,current_frame->height*sizeof(int));#ifdef HAVE_WINDOW_SYSTEMif(FRAME_WINDOW_P(frame)){bcopy(current_frame->top_left_x,temp_frame->top_left_x,current_frame->height*sizeof(short));bcopy(current_frame->top_left_y,temp_frame->top_left_y,current_frame->height*sizeof(short));bcopy(current_frame->pix_width,temp_frame->pix_width,current_frame->height*sizeof(short));bcopy(current_frame->pix_height,temp_frame->pix_height,current_frame->height*sizeof(short));bcopy(current_frame->max_ascent,temp_frame->max_ascent,current_frame->height*sizeof(short));}#endifi=j=window_size;while(i>0||j>0){p=matrix+i*(window_size+1)+j;tem=p->insertcost;if(tem<p->writecost&&tem<p->deletecost){/* Insert should be done at vpos i-1, plus maybe some before */queue[qi].count=p->insertcount;i-=p->insertcount;queue[qi++].pos=i+unchanged_at_top;}elseif(p->deletecost<p->writecost){/* Old line at vpos j-1, and maybe some before it, should be deleted */j-=p->deletecount;if(!window){set_terminal_window(window_size+unchanged_at_top);window=1;}ins_del_lines(j+unchanged_at_top,-p->deletecount);}else{/* Best thing done here is no insert or delete *//* Old line at vpos j-1 ends up at vpos i-1 */current_frame->glyphs[i+offset-1]=temp_frame->glyphs[j+offset-1];current_frame->charstarts[i+offset-1]=temp_frame->charstarts[j+offset-1];current_frame->used[i+offset-1]=temp_frame->used[j+offset-1];current_frame->highlight[i+offset-1]=temp_frame->highlight[j+offset-1];temp_frame->enable[j+offset-1]=1;i--;j--;}}if(!window&&qi){set_terminal_window(window_size+unchanged_at_top);window=1;}/* Now do all insertions */next=unchanged_at_top;for(i=qi-1;i>=0;i--){ins_del_lines(queue[i].pos,queue[i].count);/* Mark the inserted lines as clear, and put into them the line-contents strings that were discarded during the deletions. Those are the ones for which temp_frame->enable was not set. */tem=queue[i].pos;for(j=tem+queue[i].count-1;j>=tem;j--){current_frame->enable[j]=0;while(temp_frame->enable[next])next++;current_frame->glyphs[j]=temp_frame->glyphs[next];current_frame->charstarts[j]=temp_frame->charstarts[next++];}}if(window)set_terminal_window(0);}/* Determine, in matrix[i,j], the cost of updating the first j old lines into the first i new lines using the direct scrolling method. When the old line and the new line have different hash codes, the calculated cost of updating old line j into new line i includes the cost of outputting new line i, and if i != j, the cost of outputting the old line j is also included, as a penalty for moving the line and then erasing it. In addition, the cost of updating a sequence of lines with constant i - j includes the cost of scrolling the old lines into their new positions, unless i == j. Scrolling is achieved by setting the screen window to avoid affecting other lines below, and inserting or deleting lines at the top of the scrolled region. The cost of scrolling a sequence of lines includes the fixed cost of specifying a scroll region, plus a variable cost which can depend upon the number of lines involved and the distance by which they are scrolled, and an extra cost to discourage long scrolls. As reflected in the matrix, an insert or delete does not correspond directly to the insertion or deletion which is used in scrolling lines. An insert means that the value of i has increased without a corresponding increase in the value of j. A delete means that the value of j has increased without a corresponding increase in the value of i. A write means that i and j are both increased by the same amount, and that the old lines will be moved to their new positions. An insert following a delete is allowed only if i > j. A delete following an insert is allowed only if i < j. These restrictions ensure that the new lines in an insert will always be blank as an effect of the neighboring writes. Thus the calculated cost of an insert is simply the cost of outputting the new line contents. The direct cost of a delete is zero. Inserts and deletes indirectly affect the total cost through their influence on subsequent writes. *//* The vectors draw_cost, old_hash, and new_hash have the same meanings here as in calculate_scrolling, and old_draw_cost is the equivalent of draw_cost for the old line contents */staticvoidcalculate_direct_scrolling(frame,matrix,window_size,lines_below,draw_cost,old_draw_cost,old_hash,new_hash,free_at_end)FRAME_PTRframe;/* matrix is of size window_size + 1 on each side. */structmatrix_elt*matrix;intwindow_size;int*draw_cost;int*old_draw_cost;int*old_hash;int*new_hash;intfree_at_end;{registerinti,j;intframe_height=FRAME_HEIGHT(frame);registerstructmatrix_elt*p,*p1;registerintcost,cost1,delta;/* first_insert_cost[-I] is the cost of doing the first insert-line at a position I lines above the bottom line in the scroll window. */int*first_insert_cost=&FRAME_INSERT_COST(frame)[frame_height-1];int*first_delete_cost=&FRAME_DELETE_COST(frame)[frame_height-1];int*next_insert_cost=&FRAME_INSERTN_COST(frame)[frame_height-1];int*next_delete_cost=&FRAME_DELETEN_COST(frame)[frame_height-1];intscroll_overhead;/* Discourage long scrolls on fast lines. Don't scroll nearly a full frame height unless it saves at least 1/4 second. */intextra_cost=baud_rate/(10*4*FRAME_HEIGHT(frame));if(baud_rate<=0)extra_cost=1;/* Overhead of setting the scroll window, plus the extra cost cost of scrolling by a distance of one. The extra cost is added once for consistency with the cost vectors */scroll_overhead=scroll_region_cost+extra_cost;/* initialize the top left corner of the matrix */matrix->writecost=0;matrix->insertcost=INFINITY;matrix->deletecost=INFINITY;matrix->writecount=0;matrix->insertcount=0;matrix->deletecount=0;/* initialize the left edge of the matrix */cost=0;for(i=1;i<=window_size;i++){p=matrix+i*(window_size+1);cost+=draw_cost[i];p->insertcost=cost;p->writecost=INFINITY;p->deletecost=INFINITY;p->insertcount=i;p->writecount=0;p->deletecount=0;}/* initialize the top edge of the matrix */for(j=1;j<=window_size;j++){matrix[j].deletecost=0;matrix[j].writecost=INFINITY;matrix[j].insertcost=INFINITY;matrix[j].deletecount=j;matrix[j].writecount=0;matrix[j].insertcount=0;}/* `i' represents the vpos among new frame contents. `j' represents the vpos among the old frame contents. */p=matrix+window_size+2;/* matrix [1, 1] */for(i=1;i<=window_size;i++,p++)for(j=1;j<=window_size;j++,p++){/* p contains the address of matrix [i, j] *//* First calculate the cost assuming we do not insert or delete above this line. That is, if we update through line i-1 based on old lines through j-1, and then just change old line j to new line i. Depending on which choice gives the lower cost, this usually involves either scrolling a single line or extending a sequence of scrolled lines, but when i == j, no scrolling is required. */p1=p-window_size-2;/* matrix [i-1, j-1] */cost=p1->insertcost;if(cost>p1->deletecost)cost=p1->deletecost;cost1=p1->writecost;if(i==j){if(cost>cost1){cost=cost1;p->writecount=p1->writecount+1;}elsep->writecount=1;if(old_hash[j]!=new_hash[i]){cost+=draw_cost[i];}}else{if(i>j){delta=i-j;/* The cost added here for scrolling the first line by a distance N includes the overhead of setting the scroll window, the cost of inserting N lines at a position N lines above the bottom line of the window, and an extra cost which is proportional to N. */cost+=scroll_overhead+first_insert_cost[-delta]+(delta-1)*(next_insert_cost[-delta]+extra_cost);/* In the most general case, the insertion overhead and the multiply factor can grow linearly as the distance from the bottom of the window increases. The incremental cost of scrolling an additional line depends upon the rate of change of these two parameters. Each of these growth rates can be determined by a simple difference. To reduce the cumulative effects of rounding error, we vary the position at which the difference is computed. */cost1+=first_insert_cost[-j]-first_insert_cost[1-j]+(delta-1)*(next_insert_cost[-j]-next_insert_cost[1-j]);}else{delta=j-i;cost+=scroll_overhead+first_delete_cost[-delta]+(delta-1)*(next_delete_cost[-delta]+extra_cost);cost1+=first_delete_cost[-i]-first_delete_cost[1-i]+(delta-1)*(next_delete_cost[-i]-next_delete_cost[1-i]);}if(cost1<cost){cost=cost1;p->writecount=p1->writecount+1;}elsep->writecount=1;if(old_hash[j]!=new_hash[i]){cost+=draw_cost[i]+old_draw_cost[j];}}p->writecost=cost;/* Calculate the cost if we do an insert-line before outputting this line. That is, we update through line i-1 based on old lines through j, do an insert-line on line i, and then output line i from scratch, leaving old lines starting from j for reuse below. */p1=p-window_size-1;/* matrix [i-1, j] */cost=p1->writecost;/* If i > j, an insert is allowed after a delete. */if(i>j&&p1->deletecost<cost)cost=p1->deletecost;if(p1->insertcost<=cost){cost=p1->insertcost;p->insertcount=p1->insertcount+1;}elsep->insertcount=1;cost+=draw_cost[i];p->insertcost=cost;/* Calculate the cost if we do a delete line after outputting this line. That is, we update through line i based on old lines through j-1, and throw away old line j. */p1=p-1;/* matrix [i, j-1] */cost=p1->writecost;/* If i < j, a delete is allowed after an insert. */if(i<j&&p1->insertcost<cost)cost=p1->insertcost;cost1=p1->deletecost;if(p1->deletecost<=cost){cost=p1->deletecost;p->deletecount=p1->deletecount+1;}elsep->deletecount=1;p->deletecost=cost;}}/* Perform insert-lines and delete-lines operations on FRAME according to the costs in MATRIX, using the direct scrolling method. Update the frame's current_glyphs info to record what was done. WINDOW_SIZE is the number of lines being considered for scrolling and UNCHANGED_AT_TOP is the vpos of the first line being considered. These two arguments can specify any contiguous range of lines. We also shuffle the charstarts vectors for the lines along with the glyphs; but the results are not quite right, since we cannot offset them for changes in amount of text in this line or that line. Luckily it doesn't matter, since update_frame and update_line will copy in the proper new charstarts vectors from the frame's desired_glyphs. In the direct scrolling method, a new scroll window is selected before each insertion or deletion, so that groups of lines can be scrolled directly to their final vertical positions. This method is described in more detail in calculate_direct_scrolling, where the cost matrix for this approach is constructed. */staticvoiddo_direct_scrolling(frame,matrix,window_size,unchanged_at_top)FRAME_PTRframe;structmatrix_elt*matrix;intwindow_size;intunchanged_at_top;{registerstructmatrix_elt*p;registerinti,j;registerstructframe_glyphs*current_frame;/* temp_frame->enable[i] means line i has been moved to current_frame. */registerstructframe_glyphs*temp_frame;structalt_queue{intcount,pos,window;}*queue;intoffset=unchanged_at_top;intqi=0;intwindow=0;registerinttem;intnext;/* A nonzero value of write_follows indicates that a write has been selected, allowing either an insert or a delete to be selected next. When write_follows is zero, a delete cannot be selected unless j < i, and an insert cannot be selected unless i < j. This corresponds to a similar restriction (with the ordering reversed) in calculate_direct_scrolling, which is intended to ensure that lines marked as inserted will be blank. */intwrite_follows=1;queue=(structalt_queue*)alloca(FRAME_HEIGHT(frame)*sizeof(structalt_queue));current_frame=FRAME_CURRENT_GLYPHS(frame);temp_frame=FRAME_TEMP_GLYPHS(frame);bcopy(current_frame->glyphs,temp_frame->glyphs,current_frame->height*sizeof(GLYPH*));bcopy(current_frame->charstarts,temp_frame->charstarts,current_frame->height*sizeof(GLYPH*));bcopy(current_frame->used,temp_frame->used,current_frame->height*sizeof(int));bcopy(current_frame->highlight,temp_frame->highlight,current_frame->height*sizeof(char));bzero(temp_frame->enable,temp_frame->height*sizeof(char));bcopy(current_frame->bufp,temp_frame->bufp,current_frame->height*sizeof(int));#ifdef HAVE_WINDOW_SYSTEMif(FRAME_WINDOW_P(frame)){bcopy(current_frame->top_left_x,temp_frame->top_left_x,current_frame->height*sizeof(short));bcopy(current_frame->top_left_y,temp_frame->top_left_y,current_frame->height*sizeof(short));bcopy(current_frame->pix_width,temp_frame->pix_width,current_frame->height*sizeof(short));bcopy(current_frame->pix_height,temp_frame->pix_height,current_frame->height*sizeof(short));bcopy(current_frame->max_ascent,temp_frame->max_ascent,current_frame->height*sizeof(short));}#endifi=j=window_size;while(i>0||j>0){p=matrix+i*(window_size+1)+j;tem=p->insertcost;if(tem<p->writecost&&tem<p->deletecost&&(write_follows||i<j)){/* Insert should be done at vpos i-1, plus maybe some before. Setting count to 0 in the queue marks this as an insert. */write_follows=0;queue[qi].window=i+unchanged_at_top;queue[qi].count=0;i-=p->insertcount;queue[qi++].pos=i+unchanged_at_top;}elseif(p->deletecost<p->writecost&&(write_follows||i>j)){/* Delete should be done at vpos j-1, plus maybe some before. */write_follows=0;j-=p->deletecount;}else{/* One or more lines should be retained. */write_follows=1;tem=p->writecount;if(i>j){/* Immediately scroll a group of lines downward */set_terminal_window(i+unchanged_at_top);window=1;ins_del_lines(j-tem+unchanged_at_top,i-j);}elseif(i<j){/* Queue the upward scrolling of a group of lines */queue[qi].pos=i-tem+unchanged_at_top;queue[qi].window=j+unchanged_at_top;queue[qi++].count=i-j;}/* Now copy the line-contents strings */while(tem>0){i--;j--;tem--;current_frame->glyphs[i+offset]=temp_frame->glyphs[j+offset];current_frame->charstarts[i+offset]=temp_frame->charstarts[j+offset];current_frame->used[i+offset]=temp_frame->used[j+offset];current_frame->highlight[i+offset]=temp_frame->highlight[j+offset];temp_frame->enable[j+offset]=1;}}}/* Now do all the upward scrolling, and copy the line-contents strings for the blank lines of the recorded inserts. */next=unchanged_at_top;for(i=qi-1;i>=0;i--){if(queue[i].count){set_terminal_window(queue[i].window);window=1;ins_del_lines(queue[i].pos,queue[i].count);}else{/* Mark the inserted lines as clear, and put into them the line-contents strings that were discarded during the deletions. Those are the ones for which temp_frame->enable was not set. */tem=queue[i].pos;for(j=queue[i].window-1;j>=tem;j--){current_frame->enable[j]=0;while(temp_frame->enable[next])next++;current_frame->glyphs[j]=temp_frame->glyphs[next];current_frame->charstarts[j]=temp_frame->charstarts[next++];}}}if(window)set_terminal_window(0);}voidscrolling_1(frame,window_size,unchanged_at_top,unchanged_at_bottom,draw_cost,old_draw_cost,old_hash,new_hash,free_at_end)FRAME_PTRframe;intwindow_size,unchanged_at_top,unchanged_at_bottom;int*draw_cost;int*old_draw_cost;int*old_hash;int*new_hash;intfree_at_end;{structmatrix_elt*matrix;matrix=((structmatrix_elt*)alloca((window_size+1)*(window_size+1)*sizeof*matrix));if(scroll_region_ok){calculate_direct_scrolling(frame,matrix,window_size,unchanged_at_bottom,draw_cost,old_draw_cost,old_hash,new_hash,free_at_end);do_direct_scrolling(frame,matrix,window_size,unchanged_at_top);}else{calculate_scrolling(frame,matrix,window_size,unchanged_at_bottom,draw_cost,old_hash,new_hash,free_at_end);do_scrolling(frame,matrix,window_size,unchanged_at_top);}}/* Return number of lines in common between current and desired frame contents described to us only as vectors of hash codes OLDHASH and NEWHASH. Consider only vpos range START to END (not including END). Ignore short lines on the assumption that avoiding redrawing such a line will have little weight. */intscrolling_max_lines_saved(start,end,oldhash,newhash,cost)intstart,end;int*oldhash,*newhash,*cost;{struct{inthash;intcount;}lines[01000];registerinti,h;registerintmatchcount=0;intavg_length=0;intthreshold;/* Compute a threshold which is 1/4 of average length of these lines. */for(i=start;i<end;i++)avg_length+=cost[i];avg_length/=end-start;threshold=avg_length/4;bzero(lines,sizeoflines);/* Put new lines' hash codes in hash table. Ignore lines shorter than the threshold. Thus, if the lines that are in common are mainly the ones that are short, they won't count. */for(i=start;i<end;i++){if(cost[i]>threshold){h=newhash[i]&0777;lines[h].hash=newhash[i];lines[h].count++;}}/* Look up old line hash codes in the hash table. Count number of matches between old lines and new. */for(i=start;i<end;i++){h=oldhash[i]&0777;if(oldhash[i]==lines[h].hash){matchcount++;if(--lines[h].count==0)lines[h].hash=0;}}returnmatchcount;}/* Return a measure of the cost of moving the lines starting with vpos FROM, up to but not including vpos TO, down by AMOUNT lines (AMOUNT may be negative). These are the same arguments that might be given to scroll_frame_lines to perform this scrolling. */scroll_cost(frame,from,to,amount)FRAME_PTRframe;intfrom,to,amount;{/* Compute how many lines, at bottom of frame, will not be involved in actual motion. */intlimit=to;intoffset;intheight=FRAME_HEIGHT(frame);if(amount==0)return0;if(!scroll_region_ok)limit=height;elseif(amount>0)limit+=amount;if(amount<0){inttemp=to;to=from+amount;from=temp+amount;amount=-amount;}offset=height-limit;return(FRAME_INSERT_COST(frame)[offset+from]+(amount-1)*FRAME_INSERTN_COST(frame)[offset+from]+FRAME_DELETE_COST(frame)[offset+to]+(amount-1)*FRAME_DELETEN_COST(frame)[offset+to]);}/* Calculate the line insertion/deletion overhead and multiply factor values */staticvoidline_ins_del(frame,ov1,pf1,ovn,pfn,ov,mf)FRAME_PTRframe;intov1,ovn;intpf1,pfn;registerint*ov,*mf;{registerinti;registerintframe_height=FRAME_HEIGHT(frame);registerintinsert_overhead=ov1*10;registerintnext_insert_cost=ovn*10;for(i=frame_height-1;i>=0;i--){mf[i]=next_insert_cost/10;next_insert_cost+=pfn;ov[i]=(insert_overhead+next_insert_cost)/10;insert_overhead+=pf1;}}staticvoidins_del_costs(frame,one_line_string,multi_string,setup_string,cleanup_string,costvec,ncostvec,coefficient)FRAME_PTRframe;char*one_line_string,*multi_string;char*setup_string,*cleanup_string;int*costvec,*ncostvec;intcoefficient;{if(multi_string)line_ins_del(frame,string_cost(multi_string)*coefficient,per_line_cost(multi_string)*coefficient,0,0,costvec,ncostvec);elseif(one_line_string)line_ins_del(frame,string_cost(setup_string)+string_cost(cleanup_string),0,string_cost(one_line_string),per_line_cost(one_line_string),costvec,ncostvec);elseline_ins_del(frame,9999,0,9999,0,costvec,ncostvec);}/* Calculate the insert and delete line costs. Note that this is done even when running with a window system because we want to know how long scrolling takes (and avoid it). This must be redone whenever the frame height changes. We keep the ID costs in a precomputed array based on the position at which the I or D is performed. Also, there are two kinds of ID costs: the "once-only" and the "repeated". This is to handle both those terminals that are able to insert N lines at a time (once- only) and those that must repeatedly insert one line. The cost to insert N lines at line L is [tt.t_ILov + (frame_height + 1 - L) * tt.t_ILpf] + N * [tt.t_ILnov + (frame_height + 1 - L) * tt.t_ILnpf] ILov represents the basic insert line overhead. ILpf is the padding required to allow the terminal time to move a line: insertion at line L changes (frame_height + 1 - L) lines. The first bracketed expression above is the overhead; the second is the multiply factor. Both are dependent only on the position at which the insert is performed. We store the overhead in FRAME_INSERT_COST (frame) and the multiply factor in FRAME_INSERTN_COST (frame). Note however that any insertion must include at least one multiply factor. Rather than compute this as FRAME_INSERT_COST (frame)[line]+FRAME_INSERTN_COST (frame)[line], we add FRAME_INSERTN_COST (frame) into FRAME_INSERT_COST (frame). This is reasonable because of the particular algorithm used in calcM. Deletion is essentially the same as insertion. */do_line_insertion_deletion_costs(frame,ins_line_string,multi_ins_string,del_line_string,multi_del_string,setup_string,cleanup_string,coefficient)FRAME_PTRframe;char*ins_line_string,*multi_ins_string;char*del_line_string,*multi_del_string;char*setup_string,*cleanup_string;intcoefficient;{if(FRAME_INSERT_COST(frame)!=0){FRAME_INSERT_COST(frame)=(int*)xrealloc(FRAME_INSERT_COST(frame),FRAME_HEIGHT(frame)*sizeof(int));FRAME_DELETEN_COST(frame)=(int*)xrealloc(FRAME_DELETEN_COST(frame),FRAME_HEIGHT(frame)*sizeof(int));FRAME_INSERTN_COST(frame)=(int*)xrealloc(FRAME_INSERTN_COST(frame),FRAME_HEIGHT(frame)*sizeof(int));FRAME_DELETE_COST(frame)=(int*)xrealloc(FRAME_DELETE_COST(frame),FRAME_HEIGHT(frame)*sizeof(int));}else{FRAME_INSERT_COST(frame)=(int*)xmalloc(FRAME_HEIGHT(frame)*sizeof(int));FRAME_DELETEN_COST(frame)=(int*)xmalloc(FRAME_HEIGHT(frame)*sizeof(int));FRAME_INSERTN_COST(frame)=(int*)xmalloc(FRAME_HEIGHT(frame)*sizeof(int));FRAME_DELETE_COST(frame)=(int*)xmalloc(FRAME_HEIGHT(frame)*sizeof(int));}ins_del_costs(frame,ins_line_string,multi_ins_string,setup_string,cleanup_string,FRAME_INSERT_COST(frame),FRAME_INSERTN_COST(frame),coefficient);ins_del_costs(frame,del_line_string,multi_del_string,setup_string,cleanup_string,FRAME_DELETE_COST(frame),FRAME_DELETEN_COST(frame),coefficient);}